I'm in the process of doing my first build and one of the problems I ran into right off is that I have no available OVEN that will hold a barreled receiver. Not even the gas grill is big enough.

This means that I will have to PAINT subassemblies and then press in the barrel for the paint jobs.

Anyway, Christmas/parties is a 6 week preparation thing around here so the full park and paint thing will have to wait until after the holidays.

In the meantime I gotta do something so I'm working up my first Romy kit. I did a good demil and it was just waiting for the next step.

So, I took my little hand held blaster and some 120 grit aluminum oxide and gave the entire bunch of parts a good even blasting. Learned a lot there, you GOTTA have a recovery box for the media.

Anyway, what this involves is a thorough degreasing, handing the metal parts with gloves, some swabs of some type, like a cotton ball and a clothespin and a bottle of Brownell's RUST BLUE.

This is a bottle of hydrocloric and nitric acid that you apply to freshly blasted or sanded bare metal in a very thin, almost dry coat. Then you let the parts sit until they have a nice coat of RUST on them. This is weird, let me tell you, intentionally rusting your metal parts.

Then, you take your rusted parts and put them in a big pan of boiling WATER. Use something like a used steam table pan for this, you do not want to funk up your daily cookware.

BOIL away for at least thirty minutes. What happens is the RED OXIDE (rust) converts to BLACK OXIDE during the boil.

Boil over, take out parts with tongs or something, remember to keep them grease and oil free so keep your gloves ON.

The hot parts dry quickly so you can begin the next step right away.

CARDING. This is where you take either special stainless steel carding brushes (much faster) or just simple 0000 steel wool and brush away the black velvet looking black oxide coating. Underneath? Dark gray gunmetal.

You repeat this process until the parts have reached the depth of blue that you want. It gets easier with each application.

At the moment I am at the second boil. I have to say that I am very impressed with the results with just the first boil. It's really works well.

As a note, RUST BLUEING is the old way of coloring gunsteel. All Lugers had an original finish of rust blue as did most German firearms up untill WWII.

It is actually the premium way to BLUE a firearm. Hot Salt blueing is a shortcut.

For home builders like us, all you need is a pan that will hold the parts, a way to boil water, a stainless brush and or some 0000 steel wool and a bottle of Brownell's Classic Rust Blue.

This Romy will be a blued rifle wearing new East German plastic, it should look good.

I have used that method in the past with excellent results. I had an old Luger that I did on the kitchen stove using Herter's Belgian Rust Blue. I came out a very deep blue, almost black. It's a very good alternative to caustic salts (or painting and heating). You just need a pan big enough to get the gun in. It is the ONLY way possible to blue double barrel shotguns with solder joined barrels. Let us know how it turns out!

The finish you get with bluing is just gorgeous. Ever since I started doing it I have no desire to paint any of my guns. Bluing is easier than painting, and there's no need to cure it. I do hot salt bluing, but the finish is similar. Salt bluing though, gives a black finish not the blue you're describing.

I bought 40" bluing tanks from Brownells for $50 each shipped. They're about 8"x6"x40", and can blue the entire gun assembled.

here's a real good one I've had for awhile V and howdy to ya..
THIS METHOD OF RUST BLUEING IS EASY, AND NOT COMPLICATED AT ALL. POLISH BARREL OR PARTS, AND THEN CLEAN WITH ACITONE, KEEP HANDs OFF, WHEN DOING THE BARREL SWAB A GREASED PATCH DOWN IT AND THEN PLUG BOTH ENDS BY DRIVING IN DOWEL, OR WOOD PLUGS. NOW HANG THE BARREL IN A SMALL CONFINED SPACE, OR MAKE A GARBAGE BAG TENT OVER IT ETC. BUY A JUG OF NITRIC ACID AT YOUR LOCAL PAINT STORE, KIND USED TO CLEAN CONCRETE, POUR A OUNCE IN A JAR AND PUT IT IN WITH PART TO BE BLUED.- DO NOT DO THIS IN Y0UR SHOP-IN A FEW HOURS THE PARTS, AFTER THE ACID HAS ATTACKED IT, WILL TAKE ON A DULL FINISH. NOW KEEPING YOUR GREASY MITS OFF THE PARTS, HANG PARTS IN GARAGE OR UNDER THE EVES OF THE SHOP AND LET IT RUST. THIS WILL TAKE 3 OR 4 DAYS HERE IN OREGON, MAYBE LESS ON COAST OR BACK EAST. WHEN THERE IS A GOOD DENSE COAT OF FINE RED RUST ON EVERYTHING, CARD OR BRUSH IT DOWN TO THE BLUE,WITH A FAIRLY STIFF MOTOR DRIVEN WIRE WHEEL. THIS BLUE IS REALLY TOUGH, AND ANY AMATURE CAN DO IT. BUT USE A LITTLE COMMON SENSE WITH THE ACID, AND IF YOU LEAVE A JAR OPEN IN THE SHOP YOU WILL RUST ALL YOUR TOOLS ETC. IF YOU WANT TO BROWN A BARREL JUST STEEL WOOL DOWN THE RUST A LITTLE AND OIL.

__________________I only listen to the 14 little voices in my head,the other voices mean nothing.Voice#7-"There's Nothing That a Screwdriver to the Temple Can't Fix"SFC I Corps 68'-72'

here's a real good one I've had for awhile V and howdy to ya..
THIS METHOD OF RUST BLUEING IS EASY, AND NOT COMPLICATED AT ALL. POLISH BARREL OR PARTS, AND THEN CLEAN WITH ACITONE, KEEP HANDs OFF, WHEN DOING THE BARREL SWAB A GREASED PATCH DOWN IT AND THEN PLUG BOTH ENDS BY DRIVING IN DOWEL, OR WOOD PLUGS. NOW HANG THE BARREL IN A SMALL CONFINED SPACE, OR MAKE A GARBAGE BAG TENT OVER IT ETC. BUY A JUG OF NITRIC ACID AT YOUR LOCAL PAINT STORE, KIND USED TO CLEAN CONCRETE, POUR A OUNCE IN A JAR AND PUT IT IN WITH PART TO BE BLUED.- DO NOT DO THIS IN Y0UR SHOP-IN A FEW HOURS THE PARTS, AFTER THE ACID HAS ATTACKED IT, WILL TAKE ON A DULL FINISH. NOW KEEPING YOUR GREASY MITS OFF THE PARTS, HANG PARTS IN GARAGE OR UNDER THE EVES OF THE SHOP AND LET IT RUST. THIS WILL TAKE 3 OR 4 DAYS HERE IN OREGON, MAYBE LESS ON COAST OR BACK EAST. WHEN THERE IS A GOOD DENSE COAT OF FINE RED RUST ON EVERYTHING, CARD OR BRUSH IT DOWN TO THE BLUE,WITH A FAIRLY STIFF MOTOR DRIVEN WIRE WHEEL. THIS BLUE IS REALLY TOUGH, AND ANY AMATURE CAN DO IT. BUT USE A LITTLE COMMON SENSE WITH THE ACID, AND IF YOU LEAVE A JAR OPEN IN THE SHOP YOU WILL RUST ALL YOUR TOOLS ETC. IF YOU WANT TO BROWN A BARREL JUST STEEL WOOL DOWN THE RUST A LITTLE AND OIL.

Ya I think that is what they call FUME BLUE which is a variant of the Rust Blue process.

The ALUMINUM OXIDE ABRASIVE BLASTING GRIT I got from Brownells. This stuff ain't cheap but produces a very fine, SHARP toothed finish. You are going to need some way to trap and recover this stuff. A BIG cardboard box will catch most of it if you aim carefully and set your box up right. Or even a little bitty el cheapo harbor freight blast cabinet.http://www.brownells.com/aspx/NS/sto...LASTING%20GRIT

I DEGREASED with a shop parts washer. Followed by brake cleaner (lots of it available for free to me) and a HEAT GUN. I used 3 cans of brake clean.

HOT parts ooze oil out of everywhere there is a pin, like the RSB and the NDS receivier CENTER SUPPORT PIN. I had a acetone bath set up but didn't use it YET. I'm thinking I'm doing another degrease after this carding.

To be clear, I used the parts washer, a can of brake clean, BLASTED IT, used a can of brake clean, HEATED IT UP and used the other can of brake clean. Then started with the Rust Blue solution. With a freshly blasted dry metal surface you see the slightest oil spot.

Most of the stuff you use over and over. The Bluing acid gets used up the quickest.

Harbor Freight has two hand held blasters...either of them look like they'll do the job. When I was a mechanic I always had access to a cabinet...even after I got out of cars I could go back and get a bud to do what ever I needed...

I never thought about a hand held...they look like they'll do the trick.

+1 on Brake Clean...I ALWAYS have some around...never liked the stuff from Silo.

...Brake Clean also works good if you got a cut on you someplace...it Cleans AND disinfects!!!

...just like GumOut is a great eyeball locater. If you weren't sure where yer eyeballs were located...you WILL after ya get a little GumOut in them!

I keep both products in my garage AND my gun workshop.

I never liked putting paint on a rifle...and I'm always looking for something that will replicate a correct finish on Mil-Surplus Bolt Actions...or at least come close.

I think this stuff is gonna work out great!

CPO T

You almost should have put this part in red...its the most important part of the job...

To be clear, I used the parts washer, a can of brake clean, BLASTED IT, used a can of brake clean, HEATED IT UP and used the other can of brake clean. Then started with the Rust Blue solution. With a freshly blasted dry metal surface you see the slightest oil spot.

Remember, you are going to RUST the surface, a high polish would be de-polished by the rust. High polish isn't easy to get the proper rust on anyway.
One thing that happens is that each carding smooths the surface more and more. There is less rust with each solution application as the surface gets more polished.

With HOT BLUE you can use a blasted surface for a deep dark black-blue matt finish The finer the polish of the metal the Bluer the finish gets. All the way up to Colt's ROYAL BLUE. With HOT BLUE.

I'm looking at the $99 Harbor Freight table top blast cabinet. It's real obvious the biggest expense here is the blast media. You gotta catch and reuse it for this to be economical.

Remember, you are going to RUST the surface, a high polish would be de-polished by the rust. High polish isn't easy to get the proper rust on anyway.
One thing that happens is that each carding smooths the surface more and more. There is less rust with each solution application as the surface gets more polished.

With HOT BLUE you can use a blasted surface for a deep dark black-blue matt finish The finer the polish of the metal the Bluer the finish gets. All the way up to Colt's ROYAL BLUE. With HOT BLUE.

Like I said...I went to sleep thinking about it last night. It just keeps gettin' better and better...

This stuff could be the hot setup...no disposal problems...etc.

I see all pluses and no negatives.

Did you play hooky from work today just to work on yer guns????

I'm looking at the $99 Harbor Freight table top blast cabinet. It's real obvious the biggest expense here is the blast media. You gotta catch and reuse it for this to be economical.

When I was on active duty...in additions to keeping you all safe while ya sleep...I was...bringing stuff home...to guard and protect so the terrorists wouldn't take it and turn it agains us!!!

One of the items was a HUGE blast cabinet...it must have weighed a ton. It was too big for me so I gave it away.

One of the other things was a Verticle-Horizontal Mill...it weighs over 3,000 pounds...not only was it "not to big to keep"...I lugged it down here to NoGA when I moved!

I always wondered if this would work, how about making a sheet metal box exstension for your oven. Open the oven door , place box on door now the oven is larger to hold your barrelled receiver . you could even insulate the sides and top of the box to help retain the heat.

Another choice! I was going to use the automotive supply black oxide treatment, but now, the rust blue method will likely be the way to go.
In a related topic, I have torn down messed up old stuff and boiled the crap out of it right in the kitchen. The grease and oil gets liquified and carried away, and the hot parts dry quickly. I did restore a somewhat rough S&W Mod 10 'Victory' that way, and it's one of my best .38s now. Just a thought.

I'm up to the third of what should be at least six rustings. It's looking good so far. I'll try and get some pics up soon but it will be Sunday at the earliest.

This is a fairly slow process in the desert southwest, rust is anyway. It did rain the other night which gave a good oxididation for that day.

Pretty much you degrease it perfectly. Any oil at all and the ACID will not touch the steel, leaving an unetched (and unblued) area.

So far I have a dark gray finish that is getting darker with each rust and boil.

The boiled parts are very hot and dry very quickly. You can let the parts sit at that point until you find time to card them and then you re-apply the Rust Blue solution. Then you wait for it to get all red rusted again.

All you have to dispose of is rusty looking water and whatever paper towels and steel wool scraps you have. And your disposable gloves.

The metal is completely oil free at this point and oil makes it a couple of shades darker. I set a matte black Bulgarian mag next to it so you can judge the depth of color so far. I'm going to give it at least three more rustings and then I'll put up som e more pictures.

I like the way that looks. What do you guys think about doing that with the front and rear trunnions installed?

No problem. Doing it that way you would just want to be real sparing with the acid solution and apply it as dry as you can so that the acid doesn't penetrate into the spaces between parts. It really wouldn't hurt anything if a little does get in the cracks.

I plan on doing one more rust and brush and then will rivet the receiver together and then rust and brush the assembly a couple of times.

Nothing beats the look of a nice blued rifle . The blued color would be great for a older milled AK retro build. I am just wondering how durable the blued finish is ? I bet it is not that great . My Poly legend that is blued will rust if I look at it funny. I will stick to Gunkote over Park . Very nice looking blued finish though !

This (rust blue method of rusting + boilng + brushing) works with Beechwood Casey Blue that they sell at Wal Mart. I just tried it yesterday with a bunch of small parts for my FAL build.

The biggest part that I did from my 'small parts' batch was the trigger guard, and after three cycles it looked great. All the screws and pins and rear sight and such turned out even better than I expected.

I do not think that Liquid Blue or Super Blue from wallmart is as strong as Brownells stuff. It took a while for the rust to show.

This (rust blue method of rusting + boilng + brushing) works with Beechwood Casey Blue that they sell at Wal Mart. I just tried it yesterday with a bunch of small parts for my FAL build.

The biggest part that I did from my 'small parts' batch was the trigger guard, and after three cycles it looked great. All the screws and pins and rear sight and such turned out even better than I expected.

I do not think that Liquid Blue or Super Blue from wallmart is as strong as Brownells stuff. It took a while for the rust to show.

Heck I might try to do a whole gun this way next...

Yes, heat does help the cold blue work, but it still isn't the same as Rust Blue or Hot Salt bluing. That is unless you leave it on overnight without washing it off in humid conditions, it will cause a layer of rust to form on bare metal. I guess if you boiled it after that it would turn black.
Actual cold bluing is just selenium salts and don't offer any protection to the actual metal. Caustic Salt Bluing and Rust Bluing do provide some protection by actually adding a layer of hard oxidized metal to the metal.

Nothing beats the look of a nice blued rifle . The blued color would be great for a older milled AK retro build. I am just wondering how durable the blued finish is ? I bet it is not that great . My Poly legend that is blued will rust if I look at it funny. I will stick to Gunkote over Park . Very nice looking blued finish though !

I've had numerous German Lugers that have been through WWII that still had 98% or better of their original rust blue remaining. Pretty durable finish if you ask me. 67 years or so.

The pics are very impressive, I'm going to try this when I get time. I do have a couple of points:

I don't have any idea how much difference it makes in the process--but VALMET_M76 has referred to nitric acid and the concrete cleaning acid found in paint stores as being the same. Don't think they are. AFAIK, masonry cleaning acid is muriatic acid, which is another name for hydrochloric acid. May be a moot point. If we have a chemist on board, maybe he could tell us what difference it might make to this process.

Second, if you try this you need to know that some steel wool comes out of the package with oil in it from manufacturing. I found that out the hard way when the oil kept messing up my attempts to rust blue a muzzle loader barrel many years ago. Found out that I should have degreased the steel wool. Was told that can be done by dunking steel wool in a pan of acetone, swishing it around a bit, then draining it and repeating with clean acetone. By that time I had blued the barrel with cold blue and never tried the rust blue again.

Third, someone mentioned that metal with this form of blue will still rust, and that is true, you need to oil steel objects finished with rust blue before putting them away. Or at the very least wipe away all fingerprints and store in a dry cabinet or safe.

Yes, heat does help the cold blue work, but it still isn't the same as Rust Blue or Hot Salt bluing. That is unless you leave it on overnight without washing it off in humid conditions, it will cause a layer of rust to form on bare metal. I guess if you boiled it after that it would turn black.

Nope, it does form a rust layer after being left overnight. I figured it is not as strong as Rust Blue and still am planning on trying the real thing. But in a pinch, I had to improvise!!!